A typical EAS system in a retail setting may comprise a monitoring system and at least one security tag or marker attached to an article to be protected from unauthorized removal. The monitoring system establishes a surveillance zone in which the presence of security tags and/or markers can be detected. The surveillance zone is usually established at an access point for the controlled area (e.g., adjacent to a retail store entrance and/or exit). If an article enters the surveillance zone with an active security tag and/or marker, then an alarm may be triggered to indicate possible unauthorized removal thereof from the controlled area. In contrast, if an article is authorized for removal from the controlled area, then the security tag and/or marker thereof can be deactivated and/or detached therefrom. Consequently, the article can be carried through the surveillance zone without being detected by the monitoring system and/or without triggering the alarm.
The security tag or marker generally consists of a housing. The housing is made of a low cost plastic material, such as polystyrene. The housing is typically manufactured with a drawn cavity in the form of a rectangle. This type of housing works reasonably well, but suffers from bowing and warping that result from the drawing process introducing stresses into the plastic. In addition, the cavity crushes under stress of application or bending. An improved design was created a few years ago that added fingers or wavy ends to the label. This improvement reduces issues, but does not completely eliminate the crushing and bending issues.
A bias magnet is disposed within the housing adjacent to a magnetoelastic resonator. The bias magnet is made of a semi-hard magnetic material. The resonator is made of a soft magnetic material in the form of an elongate thin ribbon produced by rapid quenching. During operation, the security tag or marker produces a resonate signal with a particular amplitude that is detectable by the monitoring system. The resonator signal's amplitude has been conventionally enhanced by increasing a width of the resonator, whereby the production cost and complexity of the resonator is undesirably increased.